Field of the Invention
The present disclosure relates to a printing apparatus for printing supplemental information, such as a date, a print control method and a storage medium for use therewith.
Description of the Related Art
In a print obtained by performing printing on image-receiving paper via a dye-sublimation printer, an overcoat layer that protects transferred dye ink components has thermally adhered to an image-receiving layer of the image-receiving paper. The gloss of the overcoat layer varies according to the level of thermal adhesion energy (print gradation value) in thermal adhesion of the overcoat layer.
Japanese Patent Laid-Open No. 2002-240402 discloses a watermark printing technology in which the gloss of an overcoat layer is changed by changing a print gradation value to record supplemental information, such as a date, in the overcoat layer.
The level of a print gradation value changes not only the gloss but also the thickness of the overcoat layer itself. This is because, when thermal adhesion energy is high, the overcoat layer subjected to thermal adhesion contracts. For example, a large amount of heating (a high gradation value) makes the overcoat layer thinner and bluish, and a small amount of heating (a low gradation value) makes the overcoat layer thicker and reddish. As a result, supplemental information recorded in the overcoat layer has a bluish-green tint according to thermal adhesion energy in recording the supplemental information, whereas a portion (background) in which no supplemental information is recorded has a reddish tint, thereby reducing the visibility of a printed image.